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Vulnerability record · CVE-2026-26021 · published 11 February 2026

CVE-2026-26021: Set-in project set-in prototype pollution vulnerability

SSet In Project · Set In

set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.

9.4 CVSS 4.0 Critical EPSS 0.49% · top 60.3% CWE-1321 · Prototype pollution
9.4CVSS 4.0 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/ahdinosaur/set-in/commit/b8e1dabfdbd35c8d604b6324e01d03f280256c3d Patch
https://github.com/ahdinosaur/set-in/security/advisories/GHSA-2c4m-g7rx-63q7 ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-25354Set-in project set-in prototype pollution vulnerabilityThe package set-in before 2.0.3 are vulnerable to Prototype Pollution via the setIn method, as it allows an attacker to merge object prototypes into …EPSS 1.9%9.8CVE-2020-28273Set-in project set-in vulnerabilityPrototype pollution vulnerability in 'set-in' versions 1.0.0 through 2.0.0 allows attacker to cause a denial of service and may lead to remote code e…EPSS 4.0%8.6CVE-2026-34621Adobe Acrobat Reader prototype pollution leads to code executionAdobe Acrobat and Reader (versions 24.001.30356, 26.001.21367 and earlier) are affected by prototype pollution (CWE-1321) that can result in arbitrar…KEVEPSS 2.2%analysed

Source: NIST National Vulnerability Database (record CVE-2026-26021), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.